I think these are pretty nice! I do think the first one would be better if the hat was off though...the hat works in the close up picture but seems awkward and out of place on the first.
Vignetting is super easy if you have Adobe Photoshop just go to Filters, Distort, Lens Correction, remove grid (uncheck box at bottom), and then mess around with the two sliders under vignette. Note that white vignetting looks discusting HAH (in my opinion). Even easier if you have lightroom too.
People often use vignettes to draw the eye where it is supposed to go and to remove distractions in the background. Don't over use them though because they can become tacky very fast!!!